Macroporous ion exchange resin

　　Macroporous ion exchange resin is composed of styrene and propionate as monomers, ethylene benzene as crosslinking agent, toluene and xylene as pore-forming agent. They cross-link and polymerize with each other to form a porous skeleton structure.

　　Macroporous ion exchange resins are generally white spherical particles with particle sizes of 20-60 meshes. They are cross-linked polymers containing ion exchange groups. They are physicochemical stable, insoluble in acids, alkalis and organic solvents, but not affected by inorganic salts and high-strength ions or low-molecular compounds.

　　The adsorption of macroporous ion exchange resins depends on the van der Waals attraction between them and the adsorbed molecules (adsorbates). It works by its relatively large specific surface area or physical adsorption. The macroporous ion exchange resins enable organic compounds to be separated by certain solvents and elutions to remove impurities, concentrate, purify and separate according to their adsorption capacity and molecular weight. Purpose.

　　After the macroporous ion exchange resin is used for a period of time, the impurities adsorbed by the resin are approaching saturation. It is necessary to regenerate the resin and remove the ions adsorbed by the resin with chemical reagents and other impurities to restore its original composition and properties.

　　The regeneration of macroporous ion exchange resins should select appropriate regeneration agents and working conditions according to the types and characteristics of various resins and the economy of operation. The macroporous ion exchange resin and the resin with low crosslinking degree are easier to regenerate, while the gel type and the resin with high crosslinking degree will have a longer regenerative reaction time.

　　The regeneration characteristics of macroporous ion exchange resin are generally closely related to its type and structure. The regeneration of strong acidic and strong alkaline resins is more difficult than that of strong acidic and strong alkaline resins. The regeneration dosage of weak acidic or weak alkaline resins is much higher than that of theoretical ones, and the regeneration dosage of weak acidic or weak alkaline resins is only slightly more than that of theoretical values.

　　In order to reduce the cost of regeneration, the dosage of regenerant should be properly controlled so that the properties of macroporous ion exchange resin can be restored to an economical and reasonable level of regeneration. Usually, the recovery degree of control properties is 70-80%. If a higher regeneration level is to be achieved, the amount of regenerant will increase substantially, and the utilization rate of regenerant will decrease.